Module 3 Flashcards
What are the main parts of the Nervous system?
1-Central nervous system:
- brain
-spinal cord
->protected by boney structures (skull, spine)
2- peripheral nervous system:
- nerves outside the CNS
-somatic component->sensory and motor nerve
-> reacts to senses and movement respectively
3- Autonomic nervous system:
- control system of body functions (breathing, cardiovascular function, digestion etc)
- sympathetic (responding to danger) and parasympathetic (relax after stressful period)
What are the parts of the brain?
1-Brain:
Cerebrum- hippocampus, cerebral cortex, amygdala
Cerebellum
Diencephalon- thalamus, hypothalamus
Brain stem- midbrain, pons, medulla
2-Spinal cord
Note: the rigid/grooves in the brain increase surface area
Rigid : gyri
Groove : sulci
White vs Grey Matter
White (lighter pink) : Axons, Pathways between grey
Grey(darker pink) : cell bodies, dendrites, axon terminals, areas of synaptic connections
Peripheral Nerves
-nerves pointing out at every vertebrae form the peripheral nervous system
- nerves in limbs
- a nerve is a collection of many neurons (cells)
2 types:
1- motor nerves:
-efferent neurons: control effectors such as skeletal muscles
2- Sensory nerves:
-afferent neurons: detect stimuli and relay information to the CNS
Neurons
- basic information processing units->recieves input, processes info and provides output
- send action potential or stops sending action potential
Membrane potential:
- negative at rest (-70mmol)
-depolarization=membrane potential becomes positive
-repolarization/hyperpolarization=membrane potential becomes negaitive
How do Neurons work? What are the steps?
- Dendrites recieves signal from other neurons
- Axon transmit the signal over a certain distance
- Axon terminal transmits single to their neuron dendrites or tissues
- Myelin sheaths speeds up the transmission of the signal
- When the signal reaches another neuron a synapse occurs
- axon hillock determines if action potential is fired
The soma is the cell boddy
What are Glial cells?
- cells that provide support to neuron function (helps with structure, metabolism and repair)
-“helper cells”
What is a synapse?
- structure permitting communication between two neurons
What is action potential?
-change in electrical potential that can travel along a cell membrane
What are neurotransmitters?
-chemical messenger that transmits a message between cells
What are the basic steps of cell communication?
- Action potential travels down an axon
- Neurotransmitter crosses the synapse
- Neurotransmitter binds to neuroreceptors
- Trigger signal in post-synaptic neuron
Methods of measuring the nervous system
- Structure: structural imaging
- Function(behaving):
- neuronal activity- functional imaging
- EEG (electroencephalographs)
- electrophysiology
- Behaviour
-timed (reaction time)
-non-timed (errors, response)
What is bio potential?
- electric potential that is measured between two points in living cells, tissues, and organs
- electrodes, amplifiers and electrical activity
What is EEG?
Electroencephalographs
- measures electrical activity (bio potentials) arising rom the central nervous system
- neuronal activity is being measured
Depolarization/repolarization 9action potentials) is being measured
What are the different types of muscle structure?
Muscle: tissue made up of many muscle cells and associated connective tissue. There are 3 main muscle types( skeletal, cardiac and smooth)
Skeletal: (muscle fibre or myocyte) individual cell that when activated produces force that can lead to motion
Sacromere: fundamental unit of skeletal and cardiac muscle. Many , many sacromeres are arranged in sequence within a single myofibril and many myofibrils make up a muscle cell
Myofilaments: sarcomeres are composed of highly organized arrangement of myofibrils that interact with each other to generate force
Overall structure of a muscle fibre
- muscle is made up of fascicle
-fascicle are made up of muscle fibres - Muscle fibres are full of structures needed to generate force/strength
->myofibrils, sarcolemma, satellite cell, sarcoplasma - myofibrils are filled with sacromeres which are composed of thin and thick filaments or actin and myosin respectively
- z lines determine the end of the sacromere
What is a cross bridge?
-The binding of actin to myosin myofilaments and change in the confirmation of myosin
-the cross bridge cycle is the process involving attachments, conformational change and detachment (with ATP) that generates force
What is the sliding filament theory
Theory that explains the mechanism of muscle contraction associated with the gross bridge cycling and sliding of myofilaments past each other to generate force
What is a motor neuron?
Neuron that synapses with skeletal muscle cells
- can interact with millions of cells
What is a motor unit?
Motor neuron and all muscles cells that interact together
What is a neuromuscular junction?
Synapse between motor neuron and skeletal muscle
What is a muscle action potential?
Action potential on the membrane of a skeletal muscle
What are the steps to neuromscular activation?
- Depolarization of motor neuron-electrical
- Neurotransmitter release at neuromuscular junction-chemical
- Depolarization of muscle fibre-electrical
- Cross-bridge formation and sacromere shorten-mechanical
This occurs every couple of milliseconds
How can you control the amount of force a whole muscle generates?
2 ways:
1. Motor neuron recruitment- # of neurons activating or producing force
2. Action potential frequency
in general increase AP frequency =I increase in force
What determines the maximum isometric force a whole muscle could generate ?
- cross sectional area determines the max isometric force a muscle produces
- more cross bridges = more sarcomeres=more cells=more force
What is EMG?
Electromyography
- measures electrical activity produced by a muscle
2 types:
1. Surface(in the lab)
- need skin prep
-need to know muscle fibre direction
-limited by surface muscle = less accurate
- Intramuscular
- small needle inserted into a muscle
- invasive but more accurate
- need to trained
Graph:
X axis - time
Y axis - mV
An increase in force = an increase in EMG
*cant compare EMG between muscle and people
What is stimuli response?
The neural information is processed
4 steps:
1. Efferent neurons determine that a desired output is needed
2. Muscle are activated to perform task
3. Stimulus is presented in computer screen
4. Specialized cells detect the light on the screen by afferent neurons
What is reaction time dependent on?
- Stimulus intensity and modality
- Simple reaction time_only one stimulus and one response
- Choice reaction time-number of different stimuli presented each requiring different response.
What is dual-task interference?
Simultaneous performance of two tasks often leads to performance deficits in the component tasks. This effect is known as dual-task interference, is thought to be a prof of capacity limitation on cognition.
Antagonist vs Agonist
Antagonist id the muscle that relaxes during a movement
Agonist is the muscle that activists during a movement
Types of contractions
- Co-contraction:
When both the agonist and antagonist activate at the same time - Reciprocal contraction:
When the agonist and antagonist contract one after the other
What’s is biomechanics?
The study of the effects and control of forces that act on and are produced by living beings
WHat is kinematic?
The study of the motion of objects (without reference to the forces that caused the motion)
What is kinetics?
The study of forces that cause motion
2 types:
Linear
- displacement(m)
Velocity(m/s)
-acceleration(m/s^2)
Angular motion
Angular displacement (rad)
Angular velocity (rad/s)
Angular acceleration (rad/s^2)
What is force?
An action or influence that moves the body or influences the movement of the body
- internal forces are created primarily by skeletal muscles
- external forces are created by the ground external loads, other individuals and from passive sources (wind force)
-units in N
F= m x a
What is the definition of moment?
A force that tends to change the rotational motion of an object
-units are Nm
Moment arm is the perpindicular distance to the application of force
- distance between point of rotation and application of force
M= Fx d
F=force
D=perpendicular distance between axis of rotation and line of force
What id the COM?
Centre of mass
- point in an object where the mass of the object is equally distributed in all directions
- the force of gravity is equal to mass(acceleration) due to gravity
F=mxa
= m (9.8 m/s^2)
How can kinematic be measured?
Visual observation
Goinometer->measure joint angle
- hand held and electric
Inertial sensors( Apple Watch sensory devices)
optical or magnetic motion capture
- gold standard for measuring kinematic
- expensive
- requires knowledge of software
- best technique, reliable and accurate
What are the ways to measure kinetics?
Manual assessment
- do anywhere, by anyone, need training
Dynamometer-device measures force, moment of power
- hand held-> accurate
- electronic (isokinetic)->measure force produced by grip, expensive, control variable, speed of contractions, joint angle
Force plates
- gold standard of measuring kinetics
- super accurate
- very pricey
What do you need to picture the movement
-EMG
-Kinetic data(forces)
- kinematic (movement data)
